Sliding Sleeve Having Contracting, Dual Segmented Ball Seat

Abstract

A sliding sleeve opens with a deployed ball. The sleeve has a seat disposed in the housing, and the seat has segments biased outward from one another with a C-ring or other biasing element. Initially, the seat has an expanded state in the sliding sleeve so that the seats segments expand outward against the housing's bore. When an appropriately sized ball is deployed downhole, the ball engages the expanded seat. Fluid pressure applied against the seated ball moves the seat into the inner sleeve's bore. As this occurs, the seat contracts, which increases the engagement area of the seat with the ball. Eventually, the seat reaches the shoulder in the inner sleeve so that pressure applied against the seated ball now moves the inner sleeve in the housing to open the sliding sleeve's flow port.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Appl. No. 61 / 736,993, filed 13, Dec., -2012, which is incorporated herein by reference.BACKGROUND OF THE DISCLOSURE[0002]In a staged fracturing operation, multiple zones of a formation need to be isolated sequentially for treatment. To achieve this, operators install a fracturing assembly down the wellbore, which typically has a top liner packer, open hole packers isolating the wellbore into zones, various sliding sleeves, and a wellbore isolation valve. When the zones do not need to be closed after opening, operators may use single shot sliding sleeves for the fracturing treatment. These types of sleeves are usually ball-actuated and lock open once actuated. Another type of sleeve is also ball-actuated, but can be shifted closed after opening.[0003]Initially, operators run the fracturing assembly in the wellbore with all of the sliding sleeves closed and with the wellbore isolation ...

AI Technical Summary

Benefits of technology

The patent describes a sliding sleeve assembly for use in oil and gas wells. The assembly includes a sliding sleeve with a seat that can open the inner sleeve to allow fluid to flow through. The seat has segments that move outward to engage the ball and support it. The seat can be opened with a deployed ball and the pressure applied against it. The sliding sleeve can be used in a treatment operation to fracture or perform other operations. The technical effect of the patent is to provide a reliable and effective tool for oil and gas well drilling and treatment operations.

Problems solved by technology

Despite the effectiveness of such an assembly, practical limitations restrict the number of balls B that can be effectively run in a single tubing string.

Depending on the pressures applied and the composition of the ball B used, a number of detrimental effects may result.

This practical limitation restricts how many balls B can be used for seats 40 in an assembly of sliding sleeves 10.

Additionally, aluminum balls B can be particularly difficult to mill out of the sliding sleeve 10 due to their tendency of rotating during the milling operation.

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